Aqueous composition for preparing hard capsule, preparation method therefor, hard capsule, and method for recycling hard capsule scraps

ABSTRACT

Disclosed are an aqueous composition for preparing a hard capsule, a preparation method therefor, a hard capsule, and a method for recycling hard capsule scraps. The disclosed aqueous composition for preparing a hard capsule comprises a water-soluble cellulose ether, an alcohol, and water. In addition, the method for recycling hard capsule scraps comprises the step of dissolving hard capsule scraps comprising a water-soluble cellulose ether into a mixture solution comprising water and an alcohol so as to prepare an aqueous composition for preparing a recycled hard capsule.

TECHNICAL FIELD

One or more embodiments of the present invention relate to an aqueouscomposition for preparing a hard capsule, a method of preparing thesame, a hard capsule prepared by using the aqueous composition, and amethod of recycling a hard capsule scrap. In particular, one or moreembodiments of the present invention relate to an aqueous compositionfor preparing a hard capsule, including a water-soluble cellulose etherand an alcohol, a method of preparing the same, a hard capsule preparedby using the aqueous composition, and a method of cycling a hard capsulescrap which is produced when a hard capsule is prepared.

BACKGROUND ART

In general, hard capsules have been prepared by using gelatin derivedfrom bovines or swine. A Scrap, which is produced in the manufacturingprocedure of a gelain hard capsule, has the same gel characteristics asgelatin, when the scrap is dissolved in high-temperature water and thencooled to room temperature. Accordingly, the scrap can be recycled as ahard capsule. Thus, when a hard capsule is prepared by using gelatin,capsule production costs may reduce, which is why most capsulemanufacturers prefer to the production of a gelatin hard capsule.

Gelatin-containing aqueous compositions are prepared for a relativelyshort time period due to the direct dissolution of gelatin inhigh-temperature water (for example, 60° C.), and when a mold pin isimmersed therein and then taken therefrom to dry the gelatin-containingaqueous compositions coated on the mold pin, the drying time is shortand the obtained hard capsule may have excellent elasticity, glossiness,and disintegrability, and the production yield of the hard capsule isvery high. However, the recent outbreak of the mad cow diseases reducesuse of gelatin, and accordingly, capsules prepared by using celluloseether that is a vegetable material, instead of the gelatin, are gettingmuch attention.

However, although cellulose ether is dissolved in room temperature (25°C.) water, immediately when added into water, most of the celluloseether aggregates to form an aggregate, requiring a long time forcomplete dissolution. To prevent this problem, when an aqueouscomposition for preparing a hard capsule is prepared, cellulose ether isadded to high temperature (for example, 80° C. or higher) water toprevent the aggregation and then dispersed well to prepare a dispersion,and then the dispersion is naturally cooled down to a first temperature(for example, 40 to 50° C.) to dissolve the dispersed cellulose ether inwater. Thereafter, the resultant is heated to a second temperature (forexample, 55 to 65° C.), and then a gelation agent and optionally agelation aid are added to the resultant. In this regard, the heating ofthe resultant to the second temperature is performed to preventsolidification of the gelation agent and gelation aid. However,cellulose ether may not be completely dissolved in water at the secondtemperature, and thus an aqueous composition and a final hard capsuleincluding cellulose ether may have the following disadvantages:

(1) the aqueous composition may have a varying viscosity according tolocation and also may undergo a layer-separation during a long-termstorage;

(2) a degree of mixing of cellulose ether and a gelation agent (andoptionally, a gelation aid) in the aqueous composition may decrease,thereby requiring more of the gelation agent (and optionally, a gelationaid) to be added thereto;

(3) the aqueous composition may have a low filtering efficiency in asubsequent filtering process for removing foreign materials (forexample, fiber) therefrom;

(4) even after the filtering, foreign materials may remain in theaqueous composition to deteriorate performance of a capsulation agentand/or a capsulation aid, leading to a decrease in moldability orformability;

(5) when a drying process is performed to evaporate water in the aqueouscomposition doped on a substrate (for example, mold pin) in a capsulemolding process, a drying speed of the aqueous composition is low;

(6) the preparation time and drying time of the aqueous composition arelong, and thus, the production yield of a hard capsule is low; and

(7) foreign materials remaining in the aqueous composition are includedin a hard capsule, which is a final product, and due to the includedforeign materials, the quality (elasticity, glossiness,disintegrability, or the like) of the hard capsule decreases, and it isdifficult to keep the quality of a hard capsule constant for allproduction lots.

Also, when a hard capsule is prepared by using cellulose ether, scrap,which is produced in the manufacturing procedure of the hard capsule,forms a high-viscosity solution when dissolved in water. Accordingly, itis difficult for the scrap to be dissolved at high concentration, andalso, the high-viscosity solution does not have gel characteristics.Thus, the recycling of the scrap as a hard capsule is difficult.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

The present invention provides an aqueous composition for preparing ahard capsule, including a water-soluble cellulose ether and an alcohol.

One or more embodiments of the present invention provide a method ofpreparing the aqueous composition.

One or more embodiments of the present invention provide a hard capsuleprepared by using the aqueous composition.

One or more embodiments of the present invention provide a method ofrecycling a hard capsule scrap including a water-soluble celluloseether.

Technical Solution

According to an aspect of the present invention, there is provided aAccording to an aspect of the present invention, there is provided anaqueous composition for preparing a hard capsule, wherein the aqueouscomposition includes: a water-soluble cellulose ether; an alcohol; andwater.

The aqueous composition may include 10 to 25 wt % of the water-solublecellulose ether, and 5 to 30 wt % of the alcohol.

The water-soluble cellulose ether may include hydroxypropylmethylcellulose(HPMC), hydroxyethyl methylcellulose(HEMC),methylcellulose(MC), or a mixture of two or more of these.

The alcohol may include ethanol, methanol, isopropanol, butanol, or amixture of two or more of these.

The aqueous composition may further include 0.05 to 5.0 wt % of agelation agent selected from Carrageenan, Gellan gum, Xanthan gum,Pectin, and a mixture of two or more of these.

The aqueous composition may further include more than 0 wt % and up to1.0 wt % of a gelation aid selected from potassium chloride, potassiumacetate, calcium chloride, and a mixture of two or more of these.

According to another aspect of the present invention, there is provideda method of preparing an aqueous composition for preparing a hardcapsule, wherein the method includes preparing a cellulose ethersolution that contains water, an alcohol and a water-soluble celluloseether, and that is maintained at a first temperature higher than anatmospheric temperature.

The first temperature may be in a range of 40 to 70° C.

The method may further include aging the cellulose ether solution andadding a gelation agent to the cellulose ether solution.

The aging may be performed at a temperature of 40 to 70° C. for 2 to 12hours.

According to another aspect of the present invention, there is provideda hard capsule prepared by using the aqueous composition.

According to another aspect of the present invention, there is provideda method of recycling a hard capsule scrap, wherein the method includespreparing an aqueous composition for preparing a recycled hard capsuleby dissolving the hard capsule scrap including a water-soluble celluloseether in a mixed solution including water and an alcohol.

The hard capsule scrap may include 90 to 95 parts by weight of thewater-soluble cellulose ether, 0.05 to 5.0 parts by weight of a gelationagent, 0 to 1.0 parts by weight of a gelation aid, and 1.0 to 7.0 partsby weight of water.

The step of preparing the aqueous composition for preparing a recycledhard capsule of the method of preparing a hard capsule scrap may beperformed by dissolving an additional water-soluble cellulose ethertogether with the hard capsule scrap in the mixed solution includingwater and an alcohol.

The method of recycling a hard capsule scrap may further includemaintaining the aqueous composition for preparing a recycled hardcapsule at a temperature of 40 to 70° C. for 2 to 12 hours.

The method of recycling a hard capsule scrap may further include addingat least one of an additional gelation agent and an additional gelationaid to the aqueous composition for preparing a recycled hard capsule.

The method of recycling a hard capsule scrap may further include coatingthe aqueous composition for preparing a recycled hard capsule on asubstrate and drying the aqueous composition.

The aqueous composition for preparing a recycled hard capsule mayinclude 10 to 25 wt % of the water-soluble cellulose ether and 5 to 30wt % of the alcohol.

The aqueous composition for preparing a recycled hard capsule mayinclude 0.05 to 5.0 wt % of a gelation agent.

The aqueous composition for preparing a recycled hard capsule mayfurther include more than 0 wt % and up to 1.0 wt % of a gelation aid.

Advantageous Effects

An aqueous composition for preparing a hard capsule according to anembodiment of the present invention includes water-soluble celluloseether and an alcohol. Due to the inclusion of water-soluble celluloseether and water, cellulose ether may directly dissolve in water at notonly relatively low temperature (for example, 0 to 40□) but alsorelatively high temperature (for example, 40 to 70□). Accordingly, thepreparation time for the aqueous composition may reduce, a drying timefor drying the aqueous composition when molding a capsule may reduce,and a production yield of a hard capsule, which is a final product, mayincrease. Also, a degree of mixing of cellulose ether and a gelationagent (and optionally, a gelation aid) may improve, and thus, even whenthe gelation agent (and optionally, a gelation aid) is used in smallamounts, a high-quality hard capsule may be obtained.

The manufacturing costs for a hard capsule and the disposal costs for ahard capsule scrap may reduce, and the environmental pollution mayreduce, and a high-quality hard capsule may be obtained.

DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to FIG. 1, which is a graph of a change in dryingrate over time of aqueous compositions prepared according to Examples2-5 and Comparative Examples 2-4.

BEST MODE

Hereinafter, an aqueous composition for preparing a hard capsuleaccording to an embodiment of the present invention is described indetail.

An aqueous composition (hereinafter, referred to as ┌a firstcomposition┘) for preparing a hard capsule according to an embodiment ofthe present invention includes a water-soluble cellulose ether, analcohol, and water.

The water-soluble cellulose ether is a major component of the firstcomposition. The water-soluble cellulose ether is derived from cellulosethat is a vegetable material, and is not harmful for the human body. Theterm “cellulose ether” used herein refers to a cellulose derivativeprepared by etherifying a hydroxy group of cellulose by using anetherifying agent.

The first composition may include 10 to 25 wt % of the water-solublecellulose ether. When the amount of the water-soluble cellulose ether iswithin this range, an appropriate level of viscosity may be obtained.Thus, bubbles may be easily removed from the aqueous composition, and anappropriate thickness of capsules may be obtained.

The water-soluble cellulose ether may include hydroxypropylmethylcellulose (HPMC), hydroxyethyl methylcellulose (NEMC),methylcellulose (MC), or a mixture of two or more of these.

The alcohol may help the water-soluble ether liquefy (i.e., dissolve) inthe first composition. This process is described in more detail asfollows: when the water-soluble cellulose ether is added to lowtemperature (20 to 30° C.) water, a part of the water-soluble celluloseether that directly contacts water dissolves and a part of thewater-soluble cellulose ether that does not directly contact wateraggregates to form a lump, and when the water-soluble cellulose ether isadded to high temperature (40 to 70° C.) water, even the part of thewater-soluble cellulose ether that directly contacts water does notdissolve well. However, the alcohol is mixed with water to form anaqueous alcohol solution, and the water-soluble cellulose etherdissolves well in not only a low temperature (20 to 30° C.) aqueousalcohol solution but also a high temperature (40 to 70° C.) aqueousalcohol solution.

The first composition may include 5 to 30 wt % of the alcohol. When theamount of the alcohol is within this range, solubility of celluloseether increases and an evaporation speed of the alcohol during thepreparation of a capsule is at an appropriate level so that awrinkle-free smooth capsule film may be obtained.

The alcohol may include ethanol, methanol, isopropanol, butanol, or amixture of two or more of these.

The first composition may further include 0.05 to 5.0 wt % of a gelationagent. When the amount of the gelation agent is within this range, aviscosity of the first composition may appropriately increase, and thusa hard capsule formed by using the gelation agent may have increasedelongation at break and decreased brittleness.

The gelation agent may include a water-soluble gum.

The water-soluble gum may include Carrageenan, Gellan gum, Xanthan gum,Pectin, or a mixture of two or more of these.

The first composition may further include more than 0 wt % and up to 1.0wt % of a gelation aid. When the amount of the gelation aid is withinthis range, a gelation ability of the gelation agent may improve andthus, the first composition may have excellent capsule moldability, anda haze-free hard capsule may be obtained.

The gelation aid may include potassium chloride, potassium acetate,calcium chloride, or a mixture of two or more of these.

The first composition may further include 0.05 to 5.0 wt % of aplasticizer. When the amount of the plasticizer is within this range, ahard capsule with high elongation at break may be obtained.

The plasticizer may include glycerol, sorbitol, propylene glycol,polyethylene glycol or a mixture of two or more of these.

When the first composition is heated to a capsule molding temperature(40 to 70° C.), the water-soluble cellulose ether may be completelydissolved. Due to the complete dissolution of the water-solublecellulose ether, the first composition may have the followingadvantages: a shorter preparation time; higher homogeneity, uniformviscosity and no layer-separation even during a period of long-termstorage; uniform viscosity for all production lots; higher capsulemoldability due to the absence of non-dissolved materials (for example,cellulose ether) that suppress performance of a gelation agent andoptionally, a gelation aid; reduction of the amount of a gelation agent(and optionally, gelation aid) due to a high degree of mixing ofcellulose ether and the gelation agent (and optionally, gelation aid); ahigh filtering efficiency in a subsequent filtering process for removingforeign materials from the first composition; a higher drying speed whena drying process for removing a solvent component from the aqueouscomposition doped on a substrate (e.g., mold pin) is performed in acapsule molding process; and a higher production yield of a hard capsuledue to shorter preparation time and drying time for the firstcomposition.

Another aspect of the present invention provides a hard capsule preparedby using the first composition. For example, the hard capsule may beprepared by immersing a room temperature (20 to 30° C.) mold pin in thefirst composition that has been heated to a high temperature (40 to 70°C.), and then taking the mold pin out of the first composition anddrying the mold pin (referred to as ‘cold pin process’).

The hard capsule has a high quality (elasticity, glossiness,disintegrability, or the like) due to the absence of a foreign material,such as fiber, in the first composition, and the quality thereof is keptconstant for all production lots.

The hard capsule may be gastric juice soluble.

Hereinafter, a method of preparing the first composition is described indetail.

The method of preparing the first composition includes preparing acellulose ether solution that includes water, an alcohol, andwater-soluble cellulose ether, and that is maintained at a firsttemperature (40 to 70° C.) that is higher than an atmospherictemperature (0 to 39° C.). In detail, the method includes mixing waterand an alcohol to prepare an aqueous alcohol solution (S1), heating theaqueous alcohol solution (S2), dissolving water-soluble cellulose etherin the heated aqueous alcohol solution to prepare a cellulose ethersolution (S3), aging the cellulose ether solution (S4), and adding agelation agent to the resultant (S5).

In the process (S2), the heating of the aqueous alcohol solution may beperformed from room temperature (20 to 30° C.) to a temperature of 40 to70° C. The process (S2) is performed to allow the water-solublecellulose ether to be dispersed well in the aqueous alcohol solution inthe process (S3) so that the water-soluble cellulose ether is easilydissolved, without aggregating. When the heating temperature is withinthis range, the gelation agent (and optionally, gelation aid) may havehigh capsule moldability without solidification, and an increase inenergy costs resulting from unnecessary heating may be minimized.

The process (S3) may be performed by slowly adding the water-solublecellulose ether to the heated aqueous alcohol solution for apredetermined period of time (for example, 1 to 2 hours) while stirring(for example, 300 rpm).

However, the present invention is not limited thereto. For example,instead of the processes (S1 to S3), water-soluble cellulose ether maybe dissolved in water (or an alcohol) to prepare a first cellulose ethersolution, and then an alcohol (or water) is added to the cellulose ethersolution to prepare a second cellulose ether solution. Also, in thiscase, (i) a water and/or an alcohol which is heated in advance is usedin the procedure of the preparation of the first and second celluloseether solutions, or (ii) the water-soluble cellulose ether is dissolvedin a room temperature (about 25° C.) water (or an alcohol) to prepare afirst cellulose ether solution, and then the first cellulose ethersolution is heated and a room temperature alcohol (or water) is addedthereto to prepare a second cellulose ether solution.

The aging process (S4) of the cellulose ether solution may be performedat a temperature of 40 to 70° C. for 2 to 12 hours. When the agingprocess (S4) is performed for this time range, bubbles may besufficiently removed from the resultant and a composition of theresultant may be homogeneous.

In the process (S4), a gelation aid and/or a plasticizer, in addition tothe gelation agent, may be further added to the resultant.

At least one process of the processes (S1 to S5) may be performed whilestirring.

The process (S5) may be additionally followed by removing bubbles fromthe first composition. This process (S5) may be performed by stirring.

The functions, kinds, and amounts of the alcohol, the water-solublecellulose ether, the gelation agent, the gelation aid, and theplasticizer are already described above, and thus explanations thereofwill be omitted herein.

Hereinafter, a method of recycling a hard capsule scrap, according to anembodiment of the present invention, will be described in detail.

A method of recycling a hard capsule scrap according to an embodiment ofthe present invention includes preparing an aqueous composition(hereinafter, referred to as ┌a second composition┘) for preparing arecycled hard capsule by dissolving the hard capsule scrap including awater-soluble cellulose ether in a mixed solution (also referred to as┌aqueous alcohol solution┘) including water and an alcohol. The term“hard capsule scrap” used herein refers to a waste material (that is,the remains after cutting) produced in the manufacturing process of ahard capsule, that is, a material that is formed of the same material asthat of the hard capsule. In detail, a primarily molded hard capsule issecondarily trimmed (that is, unnecessary parts of the hard capsule areremoved by cutting) to complete the preparation of a hard capsule havinga target appearance, and the cut parts are referred to as a hard capsulescrap.

The kinds and functions of the water-soluble cellulose ether and thealcohol are the same as or similar to those of the water-solublecellulose ether and the alcohol included in the first composition, andaccordingly, a detailed description thereof will be omitted herein.

The hard capsule scrap may include 90 to 95 parts by weight of thewater-soluble cellulose ether, 0.05 to 5.0 parts by weight of a gelationagent, 0 to 1.0 parts by weight of a gelation aid, and 1.0 to 5.0 partsby weight of the water.

The kinds and functions of the gelation agent and the gelation aid arethe same as or similar to those of the gelation agent and the gelationaid included in the first composition, and accordingly, a detaileddescription thereof will be omitted herein.

The step of preparing the second composition may be performed bydissolving an additional water-soluble cellulose ether together with thehard capsule scrap in the aqueous alcohol solution.

According to another embodiment, the step of preparing the secondcomposition may be performed by mixing (i) a solution prepared bydissolving the hard capsule scrap in an aqueous alcohol solution with(ii) a solution prepared by dissolving an additional water-solublecellulose ether in an aqueous alcohol solution.

According to another embodiment, the step of preparing the secondcomposition may be performed by preparing two or more solutions bydissolving the hard capsule scrap in an aqueous alcohol solution, andthen mixing the two or more solutions at a predetermined ratio.

The additional water-soluble cellulose ether may be the same as orsimilar to the water-soluble cellulose ether included in the hardcapsule scrap. The additional water-soluble cellulose ether may alsodissolve well in a room temperature (20 to 30° C.) and high temperature(40 to 70° C.) aqueous alcohol solutions.

In detail, the step of preparing the second composition may includepreparing an aqueous alcohol solution by mixing water and an alcohol(S10), heating the aqueous alcohol solution (S20), and dissolving thehard capsule scrap and optionally, the additional water-solublecellulose ether in the heated aqueous alcohol solution to prepare acellulose ether-containing solution (S30).

In detail, the step of preparing the second composition is similar tothe step of preparing the first composition which is described above.Accordingly, hereinafter, only a difference between these two steps willbe described.

First, in the step of preparing the second composition, as a rawmaterial, the hard capsule scrap is used instead of a separatewater-soluble cellulose ether, and the additional water-solublecellulose ether is used as an aid material. This is because the hardcapsule scrap already includes a water-soluble cellulose ether.

The step of preparing the second composition may further includemaintaining the cellulose ether-containing solution which is prepared inthe operation (S30) at a temperature of 40 to 70° C. for 2 to 12 hours(S40) (hereinafter referred to as “aging step”).

The aging step (S40) may be performed without a separate gelation agentand a separate gelation aid. This is because the hard capsule scrap mayalready include a gelation agent and a gelation aid.

However, the step of preparing the second composition may furtherinclude, after the aging step (S40), adding at least one of anadditional gelation agent and an additional gelation aid (for example,an additional gelation agent and optionally, an additional gelation aid)to the resultant of the aging step (S40). The additional gelation agentand the additional gelation aid may, respectively, be the same as orsimilar to the gelation agent and the gelation aid which are included inthe hard capsule scrap.

At least one of the additional gelation agent and the additionalgelation aid may be added to at least one step selected from all substeps included in the step of preparing the second composition.

The hard capsule scrap may further include a plasticizer. Theplasticizer may be the same as or similar to the plasticizer included inthe first composition.

Also, an additional plasticizer may be further added to at least onesteps selected from all sub steps included in the step of preparing thesecond composition. The additional plasticizer may be the same as orsimilar to the plasticizer included in the hard capsule scrap.

Components of the second composition, and amounts thereof, andadvantages in preparing the second composition, and advantages ofproperties of the second composition may be the same as or similar tothose of the first composition described above. Accordingly, a detaileddescription of these will be omitted herein.

The method of recycling a hard capsule scrap may further include coatingthe second composition on a substrate and drying the second composition.The coating and drying steps of the second composition on a substrateare the same as the coating and drying of the first composition on asubstrate to form a hard capsule. Accordingly, a detailed description ofthe coating and drying steps will be omitted herein.

Mode of the Invention

Herein, the present invention is described in detail with reference toexamples, but is not limited to the examples.

EXAMPLES 1-1 TO 1-4 AND COMPARATIVE EXAMPLE 1-1 Evaluation of HighTemperature Solubility of Cellulose Ether

Ethanol was mixed with water (purified water) at ratios shown in Table 1to prepare aqueous ethanol solutions. Thereafter, each of the aqueousethanol solutions was heated to a temperature shown in Table 1, and thenhydroxypropyl methylcellulose (HPMC)(available from Samsung FineChemical Co., Ltd., AW4) was dissolved by addition of an amount thereofas shown in Table 1 to the aqueous ethanol solution. 4 hours after HPMCwas completely dissolved, appearances of the resultant were identifiedwith the naked eye, and results thereof were evaluated based on fourlevels. The evaluation results are shown in Table 1.

(Evaluation of Appearances of the Resultant)

⊚: HPMC is very quickly dissolved, and appearances of the resultant areclear and transparent.

∘: HPMC is relatively quickly dissolved, and appearances of theresultant are clear and transparent.

Δ: HPMC is relatively slowly dissolved, and appearances of the resultantare slightly hazy.

×: HPMC is not dissolved, and appearances of the resultant are stronglyhazy.

TABLE 1 Temperature of aqueous Amounts (wt %) ethanol Water Ethanol HPMCsolution (□) appearances Example 1-1 60 20 20 60 ⊚ Example 1-2 65 15 2060 ⊚ Example 1-3 70 10 20 60 ◯ Example 1-4 75 5 20 60 Δ Comparative 80 020 60 X Example 1-1

Referring to Table 1, in the case of the resultants prepared accordingto Examples 1-1 to 1-4, HPMC was dissolved well and appearances andviscosities of the resultants were at appropriate levels. In the case ofthe resultants prepared according to Comparative Example 1-1, HPMCexists in a non-soluble state and appearances of the resultants were atinappropriate levels.

EXAMPLES 2-1 TO 2-5 Evaluation on Gelation Degree and Drying Speed ofAqueous Composition

K-carrageenan (Korea Carragheen, HG404), which is a gelation agent, andpotassium chloride, which is a gelation aid, were added according toratios shown in Table 2 below to the resultant prepared according toExample 1-2 to obtain aqueous compositions. Thereafter, gelation degreesof the respective aqueous compositions were measured according to amethod described below, and results thereof are shown in Table 2. Also,the drying speed of the aqueous composition prepared according toExample 2-5 was measured according to a method described below, andresults thereof are shown in Table 3 below.

(Gelation Degree Evaluation)

The respective aqueous compositions were sampled by using 2 ml-capacitysyringes, and then, the obtained samples were sprayed at once onto aglass plate that was perpendicularly erected. After the spraying, whenthe flow of the respective aqueous compositions flowing along the glassplate stopped, flow lengths of the respective aqueous compositions onthe glass plate were measured. Herein, the shorter flow length, thehigher the gelation degree.

(Drying Speed Evaluation)

A mold pin was immersed in the aqueous composition prepared according toExample 2-5. Thereafter, the mold pin was taken out from the aqueouscomposition and left to sit at a temperature of 25° C. and in 55% RH(relative humidity) while a weight change of the mold pin was measuredover time. Then, from the weight change of the mold pin, a drying rateof the aqueous composition was calculated. Herein, the higher dryingrate change over time, the higher drying speed. The change in weight ofthe mold pin over time and the change in the drying rate of the aqueoussolution over time are shown in Table 3 below. Also, the change in thedrying rate of the aqueous composition over time is shown in FIG. 1.

COMPARATIVE EXAMPLES 2-1 TO 2-3 Evaluation of Gelation Degree and DryingSpeed of Aqueous Compositions

Aqueous compositions of Comparative Examples 2-1 to 2-3 were prepared inthe same manner as in Examples 2-1 to 2-5, except that the resultantprepared according to Comparative Example 1-1 was used instead of theresultant prepared according to Example 1-2, and amounts ofK-Carrageenan and optionally, potassium chloride were changed. A degreeof gelation of each of the aqueous compositions was evaluated, andresults thereof are shown in Table 2. Also, a drying rate of the aqueouscompositions over time were evaluated in the same manner as in Example2-5, except that the aqueous composition prepared according toComparative Example 2-4 was used instead of the aqueous compositionprepared according to Example 2-5, and results thereof are shown inTable 3 below. Also, a change in a drying rate of the aqueouscompositions over time is shown in FIG. 1.

TABLE 2 Amounts (wt %) Gelation degree K-Carrageenan potassium chloride(cm) Example 2-1 2.0 0.0 7.0 Example 2-2 1.5 0.0 7.5 Example 2-3 1.0 0.09.0 Example 2-4 0.8 0.0 10.0 Example 2-5 1.0 0.1 7.5 Comparative 2.0 0.010.0 Example 2-1 Comparative 1.5 0.0 11.1 Example 2-2 Comparative 1.00.1 11.5 Example 2-3 Comparative 1.0 0.5 7.5 Example 2-4

Referring to Table 2, it was confirmed that the aqueous compositionsprepared according to Examples 2-1 to 2-5 had higher gelation degreesthan the aqueous compositions prepared according to Comparative Examples2-1 to 2-3 when the same or similar amounts of a gelation agent(K-Carrageenan) and a gelation aid (potassium chloride) were used.Accordingly, when an aqueous composition was manufactured according toan embodiment of the present invention, compared to when an aqueouscomposition is prepared according to a conventional method, lesseramounts of the gelation agent and the gelation aid may be used. Also, itwas confirmed that there were such amounts of the gelation agent and thegelation aid and mixed ratios thereof which are appropriate forincreasing a gelation degree of the aqueous composition. Also, in thecase of the aqueous composition prepared according to ComparativeExample 2-4, a gelation degree of the aqueous composition was high, butHPMC was not dissolved, as shown in Table 1. Accordingly, capsulemoldability of the aqueous composition may decrease, and a formed hardcapsule may have poor quality.

TABLE 3 Total weight of mold pin Weight of Weight of mold pin andaqueous composition aqueous composition Drying rate (g) (g) (g) (wt %)Comparative Comparative Comparative Comparative Time Example ExampleExample Example Example Example Example Example (min) 2-5 2-4 2-5 2-42-5 2-4 2-5 2-4 0 12.54 12.54 13.30 13.19 0.76 0.65 0.0 0.0 20 12.5412.54 13.25 13.18 0.71 0.64 6.58 1.54 40 12.54 12.54 13.19 13.14 0.650.60 14.47 7.69 60 12.54 12.54 13.09 13.09 0.55 0.55 27.63 15.38 12012.54 12.54 12.98 13.04 0.44 0.50 42.11 23.08

Referring to Table 3 and FIG. 1, it was confirmed that the aqueouscomposition prepared according to Example 2-5 had a higher drying speedthan the aqueous composition prepared according to Comparative Example2-4.

EXAMPLE 3-1 AND COMPARATIVE EXAMPLE 3-1 Evaluation on Solubility andHaze of Hard Capsule

A mold pin was immersed in each of the aqueous compositions(temperature: 60° C.) prepared according to Example 2-5 and ComparativeExample 2-4. Thereafter, the mold pins were taken out from the aqueouscompositions and then left to sit at a temperature of 25° C. and in 55%RH (relative humidity) for 1 hour to remove a solvent component from theaqueous composition by drying, thus obtaining hard capsules. Thereafter,the solubility and haze of each of the hard capsules were evaluatedaccording to methods described below, and results thereof are shown inTables 4 and 5 below.

(Evaluation of Dissolution Speed of Hard Capsule) 50 ml of water(purified water) was added into a 100 ml Erlenmeyer flask, and then atemperature of the water was maintained at 37° C. Each of the respectivehard capsules was then added into the Erlenmeyer flask, and then whilethe Erlenmeyer flask was intermittently shaken, the dissolution statesof the respective hard capsules were observed. For each of the hardcapsules, a period of time (i.e., a dissolution time) from a time when ahard capsule was added into the Erlenmeyer flask to a time when the hardcapsule was completely dissolved was recorded, and results thereof areshown in Table 4 below. Herein, the shorter dissolution time, the higherthe dissolution speed.

TABLE 4 Example 3-1 Comparative Example 3-1 Dissolution time 6 minutesand 15 seconds 8 minutes and 26 seconds

Referring to Table 4, the hard capsule prepared according to Example 3-1had a higher dissolution speed than the hard capsule prepared accordingto Comparative Example 3-1.

(Evaluation on Haze of Hard Capsule)

Each of the hard capsules was added into a 40 ml vial, and then thevials were placed in a thermo-hygrostat having conditions of atemperature 40° C. and 75% RH (relative humidity). Thereafter, each ofthe hard capsules was observed with the naked eye, and a degree ofoccurrence of haze was evaluated based on three levels as below; resultsthereof are shown in Table 5.

⊚: No change (i.e., transparency).

∘: Changed into being partially hazy.

Δ: Changed into being generally hazy.

TABLE 5 Elapsed time Example 3-1 Comparative Example 3-1 At thebeginning ⊚ ⊚ First week ⊚ ⊚ Second week ⊚ ⊚ Third week ⊚ ◯ Fourth week⊚ Δ

Referring to Table 5, the hard capsule prepared according to Example 3-1did not exhibit haze even after the hard capsule had been stored for along period of time, but the hard capsule prepared according toComparative Example 3-1 exhibited haze(after three weeks had elapsed.

EXAMPLES 4-1 AND 4-2 AND REFERENCE EXAMPLE 1-1 Preparation of AqueousComposition for Preparing Hard Capsule

Aqueous ethanol solutions were prepared by mixing ethanol and water(purified water) at ratios shown in Table 6 below. Thereafter, theaqueous ethanol solutions were heated to temperatures shown in Table 6below, and then, a hard capsule scrap and/orhydroxypropylmethylcellulose (HPMC) (AW4 available from Samsung FineChemical Co., Ltd.) were added at ratios shown in Table 6 below to theaqueous ethanol solutions and then dissolved therein. In Examples 4-1and 4-2 and Reference Example 1-1, to obtain an aqueous composition forpreparing a hard capsule containing 1.5 wt % of K-carrageenan, anappropriate amount of K-carrageenan (Korea Carragheen, HG404) wasfurther added to the aqueous ethanol solution. As a result, the aqueouscompositions for preparing a hard capsule prepared according to Examples4-1 and 4-2 and Reference Example 1-1 contained about 20 wt % HPMC or1.5 wt % K-carrageenan.

TABLE 6 Temperature Content ratio (wt %) of aqueous hard capsule ethanolWater ethanol scrap*¹ HPMC solution (° C.) Example 4-1 70 10 20 0 60Example 4-2 70 10 10 10 60 Reference 70 10 0 20 60 Example 1-1 ^(*1)Hardcapsule scrap that contained 92 wt % HPMC (AW4, available from SamsungFine Chemical Co., Ltd.), 1.2 wt % of K-carrageenan (Korea Carragheen,HG404), 0.08 wt % of KCl, 1.72 wt % of glycerol, and 5 wt % of water.

EVALUATION EXAMPLE

Regarding Examples 4-1 and 4-2 and Reference Example 1-1, 4 hours afterthe hard capsule scrap and/or HPMC was completely dissolved, theappearance of the resultant (that is, an aqueous composition forpreparing a hard capsule) was observed with naked eyes and evaluated inthe same manner as described in Examples 1-1 to 1-4 and ComparativeExample 1-1, and results thereof are shown in Table 7 below. Also,strength of gels formed from the each aqueous compositions for preparinga hard capsule prepared according to Examples 4-1 and 4-2 and ReferenceExample 1-1 and properties of films prepared from the aqueouscompositions were measured according to the following method, andresults thereof are shown in Table 7 below.

(Evaluation of Gel Strength)

The aqueous compositions for preparing a hard capsule which had beenmaintained at a temperature of 60° C. were gelated by cooling theaqueous compositions to room temperature (about 25° C.). Thereafter,strength of the gels formed from the aqueous compositions for preparinga hard capsule was measured by using a Texture Analyser (Brookfield,CT3-4500, Probe No: TA10), and results thereof are shown in Table 7below.

(Evaluation of Properties of Film)

The aqueous compositions for preparing a hard capsule which had beenmaintained at a temperature of 60° C. were coated on a glass substrateby using a film caster (directly manufactured by Samsung Fine ChemicalCo., Ltd.). Then, the glass substrate with the aqueous compositions forpreparing a hard capsule coated thereon were dried at room temperature(25° C.) for 24 hours to obtain a film having a thickness of 100 μm.Thereafter, the respective films were cut to a size of 1 cm*10 cm, andthen tensile strengths of the films were measured by using a LLOYDInstrument testing machine (LRX plus, LLOYD Instrument, UK). Also, therespective films were cut to a size of 4 cm*5 cm, and then, hardnessthereof was measured by using a Texture Analyzer (Brookfield, CT3-4500,Probe No. TA-39), and results thereof are shown in Table 7 below.

TABLE 7 Reference Example 4-1 Example 4-2 Example 1-1 Appearance ◯ ⊚ ⊚Gel strength (g) 110 120 130 Tensile strength (N/mm²) 65 62 66 Filmhardness (g) 3,230 3,110 3,200

Referring to Table 7, the aqueous compositions for preparing a hardcapsule prepared by using a hard capsule scrap and optionally, HPMCaccording to Examples 4-1 and 4-2, like the aqueous composition forpreparing a hard capsule prepared by using only HPMC according toReference Example 1-1, the hard capsule scrap and the HPMC, which wasoptionally used, were dissolved well, and thus, the appearance of theaqueous compositions looked well. Also, compared to the gel formed fromthe aqueous composition for preparing a hard capsule prepared accordingto Reference Example 1-1, at the same amount of the gelation agent(K-carrageenan), the gels formed from the aqueous compositions forpreparing a hard capsule prepared according to Examples 4-1 and 4-2 mayhave a gel strength (≧100 g) that was appropriate for the preparation ofa hard capsule, although the gel strength was slightly low. Also, thefilms prepared from the aqueous compositions for preparing a hardcapsule prepared by using a hard capsule scrap and optionally HPMCaccording to Examples 4-1 and 4-2, like the film prepared from theaqueous composition for preparing a hard capsule prepared by using onlyHPMC according to Reference Example 1-1, had appropriate levels oftensile strength and film hardness.

An aqueous composition for preparing a hard capsule according to anembodiment of the present invention includes water-soluble celluloseether and an alcohol. Due to the inclusion of water-soluble celluloseether and water, cellulose ether may directly dissolve in water at notonly relatively low temperature (for example, 0 to 40° C.) but alsorelatively high temperature (for example, 40 to 70° C.). Accordingly,the preparation time for the aqueous composition may reduce, a dryingtime for drying the aqueous composition when molding a capsule mayreduce, and a production yield of a hard capsule, which is a finalproduct, may increase. Also, a degree of mixing of cellulose ether and agelation agent (and optionally, a gelation aid) may improve, and thus,even when the gelation agent (and optionally, a gelation aid) is used insmall amounts, a high-quality hard capsule may be obtained.

According to a method of recycling a hard capsule scrap, themanufacturing costs for a hard capsule and the disposal costs for a hardcapsule scrap may reduce, and the environmental pollution may reduce,and a high-quality hard capsule may be obtained.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. An aqueous composition for preparing a hard capsule, the aqueouscomposition comprising: a water-soluble cellulose ether; an alcohol; andwater.
 2. The aqueous composition of claim 1, wherein the aqueouscomposition comprises 10 to 25 wt % of the water-soluble celluloseether, and 5 to 30 wt % of the alcohol.
 3. The aqueous composition ofclaim 1, wherein the water-soluble cellulose ether compriseshydroxypropyl methylcellulose(HPMC), hydroxyethyl methylcellulose(HEMC),methylcellulose(MC), or a mixture of two or more of these.
 4. Theaqueous composition of claim 1, wherein the alcohol comprises ethanol,methanol, isopropanol, butanol, or a mixture of two or more of these. 5.The aqueous composition of claim 1, wherein the aqueous compositionfurther comprises 0.05 to 5.0 wt % of a gelation agent selected fromCarrageenan, Gellan gum, Xanthan gum, Pectin, and a mixture of two ormore of these.
 6. The aqueous composition of claim 5, wherein theaqueous composition further comprises more than 0 wt % and up to 1.0 wt% of a gelation aid selected from potassium chloride, potassium acetate,calcium chloride, and a mixture of two or more of these.
 7. A method ofpreparing an aqueous composition for preparing a hard capsule, themethod comprising preparing a cellulose ether solution that containswater, an alcohol and a water-soluble cellulose ether, and that ismaintained at a temperature higher than an atmospheric temperature. 8.The method of claim 7, further comprising adding a gelation agent to thecellulose ether solution.
 9. A hard capsule prepared by using theaqueous composition of claim
 1. 10. A method of recycling a hard capsulescrap, the method comprising preparing an aqueous composition forpreparing a recycled hard capsule by dissolving the hard capsule scrapcontaining water-soluble cellulose ether in a mixed solution includingwater and an alcohol.
 11. The method of claim 10, wherein the hardcapsule scrap includes 90 to 95 parts by weight of the water-solublecellulose ether, 0.05 to 5.0 parts by weight of a gelation agent, 0 to1.0 parts by weight of a gelation aid, and 1.0 to 7.0 parts by weight ofwater.
 12. The method of claim 10, wherein the step of preparing theaqueous composition for preparing a recycled hard capsule comprisesdissolving additional water-soluble cellulose ether together with thehard capsule scrap in a mixed solution including water and an alcohol.13. The method of claim 10, further comprising maintaining the aqueouscomposition for preparing a recycled hard capsule at a temperature of 40to 70° C. for 2 to 12 hours.
 14. The method of claim 13, furthercomprising adding at least one of an additional gelation agent and anadditional gelation aid to the aqueous composition for preparing arecycled hard capsule.
 15. The method of claim 13, further comprisingcoating the aqueous composition for preparing a recycled hard capsule ona substrate and drying the aqueous composition.
 16. The method of claim10, wherein the aqueous composition for preparing a recycled hardcapsule includes 10 to 25 wt % of the water-soluble cellulose ether and5 to 30 wt % of the alcohol.
 17. The method of claim 10, wherein theaqueous composition for preparing a recycled hard capsule comprises 0.05to 5.0 wt % of a gelation agent.
 18. The method of claim 17, wherein theaqueous composition for preparing a recycled hard capsule furthercomprises more than 0 wt % and up to 1.0 wt % of the gelation aid.